I try to use this new tab A as a FTPserver, the Foscam (IP cam) is the ftp client. Before that I have a Samsung tab 4 (kitkat 4.4) and it ran fine (same router). Before that I had
a Toshiba window 7 as the ftpserve, no problem either. Now with this new tab A, it keep going to sleep. I was a router person before i retire, i keep checking on the router side, get no reponse from this tab A, when ping.

Thanks a lot, tested it, and it works.
Went back to look at Tab 4 (kitkat 4.4), that 'keep wifi on during sleep' was on. Might be the default on Lollipop 5.1.1 has been changed or i changed it unknowingly!
Really appreciated it. Now i can go on to test out a 'best FTPserve' app.